Hatal, Centrosome in Nerve Cells. 29 
microsomes stain intensely with eosin or erythrosin, while the 
stainable masses do not take a color with those reagents but 
only with toluidin blue, thionin or methylen blue; that is to 
say, with the basic stains. The shape of the microsome is 
nearly circular in its outline, while the stainable masses are 
generally larger in size than the microsomes and very irregular 
in outline. 
The diameter of the centrosphere is nearly constant 
measuring 3.4 4 to 4 wand being approximately the same in 
the several groups of the nerve cells. The diameter of the cen- 
trosphere is not proportional to the diameter of the cell body 
in which it lies. 
The writer noticed quite often a form of the centrosphere 
elongated in one axis and measuring 5 » in a long diameter by 
2 in the short diameter. These are probably the regular cen- 
trospheres which have become distorted, for if one takes a mean 
diameter of the two measurements, then the diameter obtained 
is quite similar to that of the ordinary form, measuring 3.4 p 
tO1'4 pL. 
As has been mentioned already, the general appearance of 
the centrosphere is quite different from that of the rest of. the 
cell body. This clearness in its appearance is greatly diminished 
by the growth changes in the cells as the animal matures, This 
fact will be discussed later on. 
The position of the sphere in the cell is variable. Al- 
though, it lies, generally, near the nucleus (Figs. I, 2, 3, 8, 9) 
in some cases, it may be somewhat removed from it (Figs. 5, 
10, 11). The stainable masses are never visible within the cen- 
trosphere, and furthermore, the protoplasmic bodies within the 
centrophere are more minute than in the remaining part of the 
cell. These two facts in a large measure account for the clear 
and transparent appearance to the centrosphere. Besides this, 
in the protoplasm there are noticeable radial lines that, no doubt, 
originate from the centrosome which occupies the central posi- 
tion in the centrosphere. The number of the radial lines varies 
in the different cells. 
